The conventional pliers generally comprise two parts which are pivotably connected to each other, and each part has a jaw. Each part has grooves defined in the outside thereof and a collar is mounted to the two parts and engaged with the grooves. When moving the collar to be engaged with different grooves, the width between the two jaws is adjusted so that the pliers can reach the pipes in a narrow space. However, the grooves are defined in the outside of each of the two parts, and the collar is mounted to the two parts increase the size of the tool, not only the manufacturing cost is increased, the tool cannot inserted into narrow space. The collar mounted to the outside of the two parts makes the pliers hulky and has odd outer appearance. Furthermore, the collar is an individual part which is easily lost.
The present invention intends to provide a pair of pliers which occupies less space.